The use of lightweight materials is an efficient way to reduce weight and improve fuel economy in vehicles. Aluminum is a promising material that can achieve 40% weight reduction while still meeting structural performance targets. For example, aluminum cross members may be used as components for lightweight truck frames. Joining aluminum cross members to steel frame rails however presents a challenge especially when the cross member is a closed section component. Pieced together joints are stiff and do not maximize weight reduction for closed section components and cross members.
Joining technology for assembling steel cross members and steel rails is well established and reliable. Generally, openings are cut through steel rails, steel cross members are placed into the openings, and are then MIG welded together. On the other hand, MIG welding aluminum cross members to steel rails is a challenging task that requires special welding techniques and equipment.
The above challenges and problems are addressed by this disclosure as well as other problems as summarized below.